Interesting update to this… I normally play SNES games using a SD2SNES. Every game I tried using, produced the noise I’m referring to. However, the Yoshi’s Island cart I just purchased plays from the same setup with ZERO NOISE.
Anyone else who has a SD2SNES, a RGB-modded SNES Jr and a OSSC with HDMI, try it out for yourself. And before anyone says it’s an issue with my SD2SNES, it sounds fine running on the same SNES with a Framemeister, and the same SD2SNES runs fine sitting in my Analogue Super Nt. Also, the sound coming out of the SNES going straight to a pair of speakers from my gscartsw sounds completely pristine. It’s only when it’s using a SD2SNES and hooked up through my OSSC that I get the noise.